Mdadm: Difference between revisions
Created page with "Mdadm is used to create linux MD raids. ==Usage== <syntaxhighlight> # Check the status of /dev/md0 mdadm -D /dev/md0 </syntaxhighlight> ===Create a raid array=== See https://www.tecmint.com/create-raid-6-in-linux/ First use gdisk to create a linux raid partition (FD00) on all your disks. Note that is purely convention and is optional. Then run the following to create /dev/md0. <syntaxhighlight lang="bash"> mdadm --create /dev/md0 --level=6 --raid-devices=4 /dev/sda1 /..." |
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==Usage== | ==Usage== | ||
<syntaxhighlight> | <syntaxhighlight lang="bash"> | ||
# Check the status of /dev/md0 | # Check the status of /dev/md0 | ||
mdadm -D /dev/md0 | mdadm -D /dev/md0 | ||
| Line 17: | Line 17: | ||
# Now you have a block device /dev/md0 on which you can add LUKS, LVM, or a filesystem. | # Now you have a block device /dev/md0 on which you can add LUKS, LVM, or a filesystem. | ||
</syntaxhighlight> | |||
===Add hot spare=== | |||
See https://tuxfixer.com/how-to-add-hot-spare-volume-to-the-existing-mdadm-software-raid-array/ | |||
<syntaxhighlight lang="bash"> | |||
mdadm --add /dev/md0 $DEVICE | |||
</syntaxhighlight> | </syntaxhighlight> | ||
==Scrubs== | ==Scrubs== | ||
On Ubuntu, md will automatically scrub on the first Sunday of every month using a systemd timer. | {{main | Archwiki:RAID#RAID_Maintenance}} | ||
On Ubuntu, md will automatically scrub on the first Sunday of every month using a systemd timer.<br> | |||
During a scrub, you can check the status with | |||
<pre> | |||
cat /proc/mdstat | |||
</pre> | |||
You can check for bad blocks using | |||
<pre> | |||
cat /sys/block/md0/md/mismatch_cnt | |||
</pre> | |||
Latest revision as of 02:51, 28 June 2023
Mdadm is used to create linux MD raids.
Usage
# Check the status of /dev/md0
mdadm -D /dev/md0
Create a raid array
See https://www.tecmint.com/create-raid-6-in-linux/
First use gdisk to create a linux raid partition (FD00) on all your disks. Note that is purely convention and is optional.
Then run the following to create /dev/md0.
mdadm --create /dev/md0 --level=6 --raid-devices=4 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1
# Now you have a block device /dev/md0 on which you can add LUKS, LVM, or a filesystem.
Add hot spare
See https://tuxfixer.com/how-to-add-hot-spare-volume-to-the-existing-mdadm-software-raid-array/
mdadm --add /dev/md0 $DEVICE
Scrubs
On Ubuntu, md will automatically scrub on the first Sunday of every month using a systemd timer.
During a scrub, you can check the status with
cat /proc/mdstat
You can check for bad blocks using
cat /sys/block/md0/md/mismatch_cnt